Lubricating oil composition

ABSTRACT

A HIGH EFFECIENCY, LUBRICATING OIL COMPOSITION COMPRISES (A) A LARGE AMOUNT OF LUBRICATING OIL, (B) A 4,4&#39;&#39;-THIOBIS PHENOL, AND (C) A SUBSTITUTED PHENOL HAVING AT LEAST ONE TERTIARY BUTYL GROUP IN THE ORTHO POSITION TO THE HYDROXYL GROUP. SAID LUBRICATING OIL COMPOSITION IS, FOR EXAMPLE, A HIGH EFFICIENCY TURBINE OIL.

United States Patent 3,745,117 LUBRICATING OIL COMPOSITION Tamotsu Fujisawa, Yamato, Genichi Tsuchihashi, Tokyo, and Toshiro Takahashi, Masanobu Nakarnura, and Yoshihiro Okada, Yokkaichi, Japan, assignors to Sagami Chemical Research Center and Daiko Oil Co., Ltd., both of Tokyo, Japan No Drawing. Filed July 19, 1971, Ser. No. 164,063 Claims priority, application Japan, Dec. 29, 1970, 46/121,577 Int. Cl. C10m 1/20, N38

US. Cl. 25248.2 5 Claims ABSTRACT OF THE DISCLOSURE A high efiiciency, lubricating oil composition comprises (a) a large amount of lubricating oil, (b) a 4,4'-thiobis phenol, and (c) a substituted phenol having at least one tertiary butyl group in the ortho position to the hydroxyl group. Said lubricating oil composition is, for example, a high efliciency turbine oil.

FIELD OF THE INVENTION This invention relates to a high efliciency lubricating oil composition and also to a process for preparing the lubricating oil composition, belonging to a mineral oil that exhibits surpassing efliciency, from a feedstock oil being devoid particularly of oxidation stability and eifect of using additives.

BACKGROUND OF THE INVENTION As regards a high efficiency lubricating oil composition, for instance, turbine oil, the use of a highly refined feedstock oil as a base oil or the use of a special composition also as a base oil has been disclosed. However, in order to prepare such a base oil, it is required to rely on a special crude oil. Further, the preparation of said base oil according to a conventional processing step is practically infeasible because of economical reasons. Still further, said special composition is least recommendable, since it is seldom available to those in the art.

SUMMARY OF THE INVENTION The inventors of the present invention have successfully overcome a series of such diificulties. It is therefore the primary object of the present invention to provide turbine oil, exhibiting surpassing efficiency comparable to a lubricating oil composition which makes use of a highly refined base oil, from crude oil.

It is another object of the present invention to provide a highly efi'icient turbine oil by use of an easily available base oil which is obtainable without particularly enhancing any refining quality thereof through a special combination of a thiobisphenol and a substituted phenol which have already proved effective as an antioxidant.

In further object, according to a process for preparing a lubricating oil by a hydrogen refining process which has given tendency to frequent adoption during the recent years, it is possible to obtain a lubricating base oil, having a property resembling that of a highly refined oil, from a conventional special crude oil. The property of the thus obtained lubricating base oil is however found to be inferior to the property in respect of stability, particularly in respect of anti-corrosive property because of 3,745,117 Patented July 10, 1973 ice copresence of aromatic components such as sulfuror nitrogen-containing heterocyclic compounds involved therein.

The present invention is, on the other hand, capable of substantially eliminating these defects.

DETAILED DESCRIPTION OF THE INVENTION In the following will be given a further embodiment of this invention, in greater detail. That is to say, the present invention covers a highly eflicient lubricating oil composition belonging to a mineral oil through the combined use of (a) 4,4-mono-, dior tri-thiobis (2,6-di-tbutylphenol), (b) other additives, and (c) a base oil having reduced oxidation stability and poor elfect from additives.

4,4-mono-, dior tri-thiobis (2,6-di-t-butylphenol) to be used in the present invention are the compounds represented by the following general formula (wherein represents an integer of from 1 to 3).

In order to obtain a lubricating oil composition of the present invention, it is required to use said 4,4-thiobis (2,6-di-t-butylphenol)s in combination with additives.

Compounds to be included in the additives in said (b) are a substituted phenol having 1 or 2 tertiary butyl groups in the ortho position to the hydroxyl group thereof, for example, 2,6-di-t-butyl-p-cresol, 2,6-di-t-butyl-4- ethylphenol, 4,4'-methylenebis (2-t-butyl-5-methylphc- 1101) and also 4,4-bis (Z-t-butyl-S-methylphenol) and the like.

The combined use of the aforementioned thiobisphenols and substituted phenols assures successful providing of a lubricating oil composition, having a favorable oxidation stability, from a base oil abundant in sulfur content. It also provides a lubricating oil composition, having surpassing property, from a high pressure hydrogen refined oil having less aromatic content. Furthermore, it is naturally a matter of course that other additives of conventional use, such as an antifoamer and a rust preventive or the like can also be used in combination with lubricating oil composition of this invention.

The amount of a thiobisphenol and the substituted phenols to be used in the present invention may vary depending on the diversified uses of the lubricating oil. The ratio of said thiobisphenols to the substituted phenols in amount may also very accordingly. Generally, a thiobisphenol is used in an amount of less than 5% by weight based on the weight of total composition, preferably in a range of from 0.01 to 0.1% by weight, while substituted phenols in an amount of less than 5% by Weight, preferably in a range of from 0.1 to 0.5% by Weight, respectively. In other words, from about 1 to about 50 parts by weight of the substituted phenol is used for each part by weight of the thiobis phenol.

According to the present invention, the use can be made of any one of various lubricating base oils having the sulfur content of approximately 5% by Weight or below.

Hereinunder will be given further embodiments the present invention in greater detail by way of examples. It should be noted however that this invention will in no way be limitative, but will merely illustrate some of the essential feature thereof. All percentages shown in following examples are based on the weight of the total composition, unless otherwise specified.

EXAMPLES 1-20 By using a solvent refined lubricating base oil, a commercially available rust preventive, an antifoamer, 0.50% of 2,6-di-tertiary butyl paracresol and thiobisphenols illustrated in Table 1, 20 turbine oil blends were prepared. Thereafter, an oxidation stability test was conducted as to each one of these turbine oils on the basis of ASTM D943. The results are shown in Table 1 to follow.

TABLE 1.-TURBINE OIL OXIDATION STABILITY TEST RESULTS ON THE BASIS OF ASTM D943 Time required for the total acid value to reach Ex. 1.0 mg. KOHI No. Composition g. (hr.)

- Base oil A .4 1,120 Base 011 A and 0.01% of organic zinc dithiophos- 1, 310

p e. 3...-- Base oil A and 0.05% S 3 3, 040 4 Base oil A and 05% SS 4 3, 690 5"...- Base oil A and 0 01% of 4 4 1, 260

cresol). 6-.." Base oil A and 0.01% S 2, 820 7..-.. Base oil A and 0.01% SS 2, 960 8 Composition in Example 2 and 0.01% S 2, 800 9.. Composition in Example 2 and 0.01% SS 2, 910 10.--- Composition in Example 2 and 0.05% SS 3, 170 11-.. Base 011 B 1 1,220 12-..- Base oil 13 and 0.01% of organic zinc dithio- 1, 340

phosphate. 13...- B880 0113 and 0.01 S 2,750 14..-- Base 011 B and 0.05% S 3,070 15.--. Base oil B and 0.01% SS 2, 860 16.... Base oil B and 0.05% SS 4 3,570 17-..- Composition in Example 12 and 0.01% S 2, 720 18- Composition in Example 12 and 0.05% S 2, 980 19-..- Composition in Example 12 and 0.01% SS 2, 690 20-..- Composition in Example 12 and 0.05% SS 3, 110

l The lubricating base oil contains 0.50% of 2,6-di-tertiary butyl paracresol. This base oil used is from the Middle East and is solvent refined It contains 0.52% of sulfur and has 31.50 centistokes of kinematic viscosity at 37.8 C. and 5.18 centistokes of kinematic viscosity at 98.9 0., respectively.

2 The lubricating base oil contains 0.50% of 2,6-di-tertiary butyl paracresol. This base oil used is from the Middle East and is solvent refined. It contains 0.32% of sulfur and has 30.30 centistokes of kinematic viscosity at 37.8 C. and 5.09 centistokes of kinematic viscosity at 98.9 C respectively.

3 4,4'-thiobis (2,6-di-t-butylphenol).

l 4,4-dithiobis (2,6-di-t-butylphenol);

Reference example.

4 Examples 21-40 By using a high pressure hydrogen refined lubricating base oil, a rust preventive (Lubrizol 859), 0.50% of 2,6- di-t-butyl-p-cresol and thiobisphenols illustrated in Table 5 2, 20 (turbine oil) compositions were prepared.

An oxidation stability test of a turbine oil was conducted on the basis of ASTM D943. The results are shown in Table 2 to follow.

TABLE 2.TURBINE OIL OXIDATION STABILITY TEST RESULTS ON THE BASIS OF ASTM D943 Time required for the total acid value to reach Ex. 1.0 mg. KOH/g N 0. Composition (hr.)

21 Base 011 C 450 22 Bas c: oil C and 0.01% of organic zinc dithiophos- 2, 260

p a e. 23-..- Base 011 C and 0.01% S 3, 120 24..-. Base oilCand 0.01% SS 3,450 25-..- Base oil 0 and 0.05% St. 3,240 26- Base oil 0 and 0.05% SS 3, 480 27 Composition in Example 22 and 0.01% 8... 2,890 28 Composition in Example 22 and 0.01% SS 3, 010 29 Composition in Example 22 and 0.05% S 3, 060 30 Composition in Example 22 and 0.05% SS 3, 180 25 31 Base oil D 800 32*. Basie oil D and 0.01% of organic zinc dithiophos- 1 100 p a e.

33 Base oil D and 0.02% of Suntorene C (trade name) 1: 570 34 Base 011 D and 0.05% of pyrollidone 1, 400 35...- Base oil D and 0.01% 8 3,310 36-.-. Base oil D and 0.01% SS 3,350 37. Composition in Example 32 and 0.01% S 3, 120 30 38 Composition in Example 32 and 0.01% 58 3, 250 39 Composition in Example 32 and 0.05% S 3, 330 40--.. Composition in Example 32 and 0.05% SS.....- 3, 490

1 Contains 2% of aromatic hydrocarbon by silica gel chromatographic analysis. It also allowed to contain 2,6-di-t-butyl para-cresol of a 0.05% high pressure hydrogen refined lubricating base oil having 28 centitstokes f kinematic viscosity at 37.8 C. and 4:98 centistokes of kinematic viscosity at 98.9 C.

2 Contains 12% of aromatic hydrocarbon through silica gel chro t graphic analysis. It also contains 2,6-di-t-butyl para-cresol a 0.50% high ressure hydrogen refined lubricating base oil having 33 centistokes of nematic viscosity at 37,8" 0. and 5.37 centistokes of klnematic viscosity at 98.9 C.

Footnotes 3 and 4-Same as in Table 1.- Reference example.

Examples 41-53 By using a solvent refined lubricating base oil from the Middle East crude oil containing, as a base oil, 0.52% of sulfur, and exhibiting a kinematic viscosity of 1.50 centistokes at 37.8 C. and 5.18 centistokes at 989 C., a rust preventive (Lubrizol 859) and also using various additives illustrated in Table 3, a catalytic oxidation test was conducted. The adding ratio of the additives and the testing results are as per illustrated in Table 3 to follow.

TABLE 3.-CATALYTIC OXIDATION TEST AT C.

0211- Total acid Formadation value, mg. tion of Example number Additive (adding ratio, weight, percent) life, hr. KOH/g. sludge 41 Reference exam le).. 2 6dit-butyl-p-cresol (0.25).....:""* r r n 360 2.4 Yes. 42 (Reference examfible)- 2: fi-di-t-butyl-p-cresol (0.25) 360 1.8 Ses 43 (Reference example 2, 2'-methy1enebis(fi-butyl-i-methylphenol) (0. 200 1.0 cs 44 (Reierence exampleg- 2, 2-methylenebis (6-butyl-4-methylphenol) (0.25)- 200 1. 0 ages. 45 (Reference example)- 4, 4-thiobis ((i-t-butyl-B-methylphenol) (0 03) 200 2.0 Yes. 46 (Reference example)- 4, 4-thiobis (2,6-di-t-butylphenol) (0.1 360 2.6 Nee. 47 (Reference example 4, 4'-thiobis (2,6-di-t -butylphenol) (0.1 360 1.2 in 48 (Reference example)- 4, 4-dithiobis (2,6-d1-t-butylphenol) (0. 360 2.1 N o. 49 (Reference example)- g't-lditlgogrs (2,6-di-{-b(1(1)tg)1phenol) (0.2 300 1.0 o. ---u --creso 50 (Reference example).{ P 6 g 360 1 0 No 2, 6-di-tu -creso 51 (Reference example).{ l g l tg g henol) (Q03) 500 1 0 No 2 6-di-tu -creso (Refmm -{4 4-dithiob is%2,6-di-t-butylphenol) 0.01 84 2, fi-di-t-butyl-p-cresol (0 5) 500 0.65 No;

in which said thiobis phenol is 4,4'-thiobis (2,6-di-t-butylbutylphenol) 4. A composition of matter comprising a 4,4'-thiobis phenol as defined in claim 1 and a substituted phenol as defined in claim 1.

5. A composition of matter comprising from about 1 to about 50 parts by weight of a substituted phenol as defined in claim 1 per each part by weight of a thiobis phenol defined in claim 1.

5 We claim: 1. A lubricating oil composition, characterized by comprising (a) a major amount of lubricating base oil; (b) from about 0.01 to 0.1 weight percent of a 4,4'- 5 thiobis phenol represented by the general formula CH: OH;

HsC-C-CH: H;C-l-CHI HiCC--CH: HIC- I CH:

1 1: V CHI 7 15 References Cited UNITED STATES PATENTS 12/1962 Cofiield 2S248.2

5/1966 Coffield 25248.2

12/1958 Dubbs et al 25252 R 5/1967 Dazzi et a1. 25250 X 9/1970 O'Neill 25252 R DANIEL E. WYMAN, Primary Examiner W. I. SHINE, Assistant Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3.7'45.ll7 Dated I Julv l0. i973 Inventor(s) TAMOTSU FUJISAWA et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, 7 line 6 replace "Daiko" with Daikyo-- Column 3, line 38 after Example No. "12'', .add an asterisk.

Column 4, line .34 in Table 2, Note 1, replace "0.05%"

with --0.50%-- j Column 4, Table 3, second column heading after "weight",

delete the comma.

Column 4,; Table 3, second column, line 2 replace "(0.25)" with --(0.5)--

Column 4, Table 3, second column, Example 44 replace (0.25) with -(O.5)

Column 4, Table 3, second column, Example 47 replace "(0.1) With -(0.2)

Column 4, Table 3, second column, Example 5 l' after "thiobis" replace (2 '6" with (2,6

Column 6, line 1 (Claim 3) replace "4,4"thiobis" with 4,4'dithiobis- Column 6, line 1 (Claim 3) delete "butyl-".

Signed and sealed this 9th day r April 19m.

(SEAL) Atte st EDWARD PLFIETCE-HERJR. C. MARSHALL DAMN Attesting Officer Commissioner of Patents FORM powso I O I USCOMM-DC 60376-P6D 9 U451 GOVERNMENT PRIN ING OFFICE I909 0-366-334,

- UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 110.. 3.745.117 Dated Julv 10 1973 Inventor(s) TAMOTSU FUJISAWA et al It is certified that error appears .in the above-identified patent ,and that said Letters Patent are hereby corrected as shown below:

Column 1, line 6 replace "Daiko" with -Daikyo Column 3, line 38 after Example No. "12'', .add an asterisk.

Column 4, line .3 4 in Table 2, Note 1, replace with --o.5o%-- w 7 7 Column 4, Table 3, second column heading afte eight", delete the comma. v

Column 4,. Table 3, second column, line 2 replace (0 .25) with --(0.5)

Column 4, Table 3, second column, Example 44 replace Column 4,- Table 3, second column, Example 47 replace "(0.1) With --(O.2)

Column 4, Table 3, second column, Example 511- after "thiobis" replace (2 '6" with 2,6-

Column 6,: line 1 (Claim 3) replace "4,4"-thiobis-" with -4,4-dithiobis-- Column 6, line 1 (Claim 3) delete "butyl-H Signed and sealed this 9th day r April 1971;.

(SEAL) Attest:

EDP-FARE) I IJLETCIEILJR. C. MARSHALLDAHN Attesting Officer Commissioner of Patents FORM po'mso (1069, l v H USCOMM-DC wan-Poo 

